Avaliação do perfil microbiano de resíduos potencialmente infectantes, sítios anatômicos e vestimentas de profissionais e seus conhecimentos de biossegurança em um serviço de atenção odontológica

Abstract

Infectious wastes are potential sources of pathogenic microorganisms, which may represent a risk for those professional who handle them as well as for the environment. Waste handlers are more susceptible to infections caused by these microorganisms when compared to other healthcare professionals. To detect a probable employee contamination from the workplace and its risk, this study aimed to evaluate the microbial content of potentially infectious waste, anatomical sites and professional gowns and their biosafety knowledge in a dental healthcare service. A 24hour generation of potentially infectious waste was collected and its quartering was conducted for obtaining the leached liquid. The microbial content of the nasal mucosa, hand and gowns was evaluated by sterile swabs. After growing in rich and selective media, the microorganisms were undergone by a morphological and biochemical screening and those considered clinically relevant were identified and had their resistance profile tested through VITEK® 2 Compact. The biofilm formation of P. aeruginosa and K. pneumoniae was evaluated by the polystyrene microplate assay at 25°C and 37°C after 4h, 24h and 48h. Other factors which favor its adherence, including hypervirulence and Extracellular polymeric substances (EPS) formation, evaluated through string test and Congo Red Agar, respectively, were also assessed. To check resistance genes and the similarity between waste and one worker P. aeruginosa samples, the reaction of polymerase chain (PCR) and the Random Amplified Polymorphic DNA (RAPD), respectively, were used. A questionnaire was administered to assess the biosecurity knowledge of employees and its results warn us about the need of regular training programs for all the institutional staffs, in which there would be discussions about the correct disposal of sharps objects, importance of vaccination, hand hygiene measures and also highlighting the waste risk and the essential elements for a correct waste management. Of the 373 microorganisms isolated in this study, 28 bacteria were isolated and 12 clinically relevant yeasts were selected for further studies. P. aeruginosa was the predominantly Gram-negative isolated, present in both waste and worker hands. S. aureus was the only clinically relevant Gram-positive isolated, recovered only in employees and C. haemulonii was the prevalent yeast specie. Approximately 60% of Gram-negative strains were resistant to ceftriaxone and cefuroxime and over half of them were resistant to ampicillin and cefoxitin. All S. aureus were resistant to benzylpenicillin. The presence of the blaTEM gene was detected in five samples of our study, including one E. coli, one K. pneumoniae, and three P. aeruginosa. K. pneumoniae was the only isolate to present a positive result for the blaSHV gene. All S. aureus strains isolated in this study were positive for blaZ gene. After thedet ection of clonal similarity between P. aeruginosa isolates, three different clusters were created and the sample recovered in the worker hands had low genetic similarity when compared to the waste ones. However, the presence of pathogens in worker hands indicates the lack of biosafety procedures. P. aeruginosa isolated in waste handler hands was the only one not to present EPS production and its biofilm was non-adherent or weakly adherent in the tested temperatures and times. In general, P. aeruginosa samples were more adherent at 25°C after 48 hours of incubation. The K. pneumoniae isolate did not show the hypervirulent phenotype and was strongly adherent at 25°C, after 24 hours of incubation. The ability of P. aeruginosa and K. pneumoniae to form strongly adherent biofilms at room temperature highlights the importance of continuous cleaning and disinfection process on surfaces and healthcare materials.